Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thuc day » thuc dan, thuc vat
dang xay » dang van, van xay
cuu tre » cau tren, cau treo
dan vai » dan va, dan tai, dan vat
thuc va » thuc vat, thuc dan
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
cua tre » cua te, cua triet, dua tren
va nam » van nam, ha nam, va nay

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky dang xay hoi. hieu va nam ((thuc va) or (thuc day)) dan vai ((cuu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang xay hoi. hieu va nam ((thuc va) OR (thuc day)) dan vai ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang xay hoi. hieu va nam ((thuc va) or (thuc day)) dan vai ((cuu tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang xay hoi. hieu va nam ((thuc va) or (thuc day)) dan vai ((cuu tre) OR (cua tre))*.